Well, "things" don't change. The particles and stuff that makes up things change, though. Imagine what it would be like if the energy levels of the electrons that accompany the atomic nuclei in your head decided all on their own to change energy levels. Or if the neutrons in a critical mass of fissionable material decided not to fiss. Or if a Higgs Boson decided to try for Chief Petty Officer, or even coxswain.